Coherent Spin-Photon Interface of single PL6 Color Centers in Silicon Carbide

TL;DR

This study thoroughly characterizes the PL6 color center in silicon carbide, demonstrating its potential as a coherent spin-photon interface with high fidelity, narrow linewidths, and extended coherence times for quantum information applications.

Contribution

It provides the first detailed experimental and theoretical analysis of the PL6 center's spin-photon interface, including spectroscopy, coherence, and entanglement properties.

Findings

Achieved 99.69% spin initialization fidelity.

Extended spin coherence time to 5.70 ms with dynamical decoupling.

Demonstrated narrow optical linewidths (~180 MHz) and high polarization visibility (~82%).

Abstract

The PL6 color center in silicon carbide has recently emerged as a promising platform for quantum information processing, yet its coherent spin--photon interface has remained largely unexplored. Here we present a comprehensive investigation of single PL6 centers, combining spectroscopy with theoretical analysis. The excited-state fine structure is fully resolved using group-theoretical modeling and strain-dependent measurements. Under resonant excitation, we achieve a spin initialization fidelity of $99.69 \pm 0.03\%$ and a readout contrast of $98.31 \pm 1.03\%$. The spin--photon--entangled $A_2$ transition exhibits narrow optical linewidths ($\sim 180$~MHz) and a polarization visibility of $\sim 82\%$. Coherent optical driving enables Rabi frequencies up to $2.895$~GHz, while dynamical decoupling extends the spin coherence time from $0.5$~ms to $5.70$~ms. Our results establish PL6 as a competitive solid-state spin--photon interface hosted in a commercially available semiconductor platform.